Root distribution and interactions between intercropped species

Abstract

Even though ecologists and agronomists have considered the spatial root distribution of plants to be important for interspecific interactions in natural and agricultural ecosystems, few experimental studies have quantified patterns of root distribution dynamics and their impacts on interspecific interactions. A field experiment was conducted to investigate the relationship between root distribution and interspecific interactions between intercropped plants. Roots were sampled twice by auger and twice by the monolith method in wheat (Triticum aestivum L.)/maize (Zea mays L.) and faba bean (Vicia faba L.)/maize intercropping and in sole wheat, maize, and faba bean up to 100 cm depth in the soil profile. The results showed that the roots of intercropped wheat spread under maize plants, and had much greater root length density (RLD) at all soil depths than sole wheat. The roots of maize intercropped with wheat were limited laterally, but had a greater RLD than sole-cropped maize. The RLD of maize intercropped with faba bean at different soil depths was influenced by intercropping to a smaller extent compared to maize intercropped with wheat. Faba bean had a relatively shallow root distribution, and the roots of intercropped maize spread underneath them. The results support the hypotheses that the overyielding of species showing benefit in the asymmetric interspecific facilitation results from greater lateral deployment of roots and increased RLD, and that compatibility of the spatial root distribution of intercropped species contributes to symmetric interspecific facilitation in the faba bean/maize intercropping.

Root exudates drive interspecific facilitation by enhancing nodulation and N 2 fixation

“…Our previous study showed that faba bean has relatively shallow roots and a limited lateral root distribution, and few roots spread under maize plants, whereas the maize roots spread under faba bean plants in an intercropping situation (37). Therefore, we used root partition, as control, to eliminate root interactions between faba bean and maize.…”

Plant: soil interactions in temperate multi-cropping production systems

“…Firstly, via asymmetric facilitation, where one crop can alter the environment of the other positively, and enhance growth of the other species. This was observed in maize (Zea mays)-wheat (Triticum aestivum) intercrops, where maize facilitated growth and nutrient uptake in wheat, but not vice versa (Li et al 2006). Similarly, compounds released by chickpea (Cicer arietinum) roots enhanced root and shoot growth in wheat, but there was no apparent effect upon the chickpea (Wang et al 2007a).…”

“…However, few studies have been carried out to systematically compare the root distribution of crops when grown in combination, rather than as sole crops. This is largely due to the technical challenges involved in studies under field conditions, and the time and costs involved (Hauggaard-Nielsen et al 2001a;Li et al 2006). Where yield advantages are manifest, this is generally considered to be due to more efficient and complementary resource use, and largely attributed to belowground interactions and root facilitation (HauggaardNielsen and Jensen 2005).…”

Crop acquisition of phosphorus, iron and zinc from soil in cereal/legume intercropping systems: a critical review

“…Spatial complementarity can occur between two crop species with contrasting root architecture, leading to exploitation of different soil horizons (Li et al, 2006;C.C. Zhang et al, 2014; Fig.…”

“…1). For example, root compatibility between intercropped maize and associated faba bean allowed intercropped maize to spread underneath the roots of neighbouring faba bean, increasing the soil space exploited for nutrients and water (Li et al, 2006). Intercropped species with contrasting phenologies (Rose et al, 2007) and/or growth periods (e.g.…”